a conventional seat device, for example, for a vehicle which includes support legs (front leg 71 and rear leg 72) respectively provided at front and rear ends of a slide rail for sliding a seat body (refer to Patent Document 1, for example) is known. Reinforcing members (side plates 73 and 74) made from plates are provided between the front and rear support legs to connect the front and rear support legs with each other. A bead (riser reinforcing portion 73a) extending in a front-rear direction is provided on the reinforcing member to enhance the reinforcing member itself.